Adebayor scored the crucial extra-time goal which allowed the Londoners to progress to the quarter-finals on the away goals rule despite a 4-1 defeat on the night in the second leg of their last-16 tie at the San Siro.

"Chants were very, very easy to hear. It's difficult for Inter, we have seen it before. It doesn't mar the game but it is something to be avoided," Villas-Boas told reporters.

Three weeks ago, Inter were fined and warned about their supporters' future conduct after racist chanting was heard during the derby with city rivals AC Milan.

Inter were fined 50,000 euros ($66,000) for its fans' repeated "expressions of racial discrimination to a player of the opposing team" and the unfurling of insulting banners.

Some hardcore Inter fans were seen waving inflatable bananas during the game.